The invention relates to an electrode system comprising an implantable, flexible electrode, particularly an epidural electrode, comprising at least one distal electrical contact. According to a further development, the electrode is arranged in an implantable, flexible catheter, particularly an epidural catheter.
Generally, such a catheter has at least one channel which, for example, is used to administrate drugs via the catheter. Sometimes, however, an electrode without a channel is also called a catheter, for example, a stimulation catheter. Such catheters with a distal electrical contact which do not comprise a channel and therefore are not a catheter in its actual sense, are subsequently called electrodes.
Catheters are known technical medical products which are manufactured for various intended purposes of usage in diagnostics or therapy. For example, epidural catheters are known which can be inserted by a physician into the epidural space in the region of the spinal canal so as to be able to inject pain-killing drugs, for example. Such a method is particularly applied in treatment of chronic pain. The catheter can remain in the body for a time period of 1 to 30 days, for example, and the injection of the drugs can be effected through external or implanted pumps.
Instead of catheters also electrodes are used in therapy of chronic pain. For example, electrodes for implantation are known which are connected to a pulse generator for permanent stimulation of the spinal cord or the nerves.
Moreover, special needles are known which are connected to a generator of pulsed high frequency. Such special needles and high frequency generators are used to trigger the release of pain-inhibiting substances in the spinal cord by selectively stimulating nerves, thereby effecting a pain treatment. However, usage of these special needles is frequently limited due to anatomical reasons or is avoided because of the risk of injury at introducing the special needles.
From EP 1 181 947 A2, an epidural catheter is known having at least three electrodes arranged in line. The electrodes serve to electrically stimulate nerves or the spinal cord. A channel for administration of drugs can be provided, so that, in addition to the electrical stimulation of the spinal cord or the spinal nerves, an injection of pain-killing drugs is possible.
A further implantable epidural catheter is known from DE 203 08 422 U1. This catheter is, for example, suitable for applying pulsed high frequency for stimulation of nerves. Furthermore, a syringe or a drug pump can be connected. The catheter comprises a fixation member which can serve to fasten the catheter at a point of entry into a body and through which electrical leads and a hose line of the catheter are led.